Compatible with the HK MP5 and its clones including the PTR9 the ProMag HK MP5 / PTR9 9mm 40-Round Magazine features a durable DuPont Zytel polymer body with reinforced feed lips for natural corrosion resistance and unparalleled durability delivering reliable and consistent operation in virtually any shooting environment. The high-tensile chrome silicon wire spring and injection-molded DuPont Zytel polymer follower ensure smooth jam-free operation. Backed by ProMag's legendary lifetime warranty for superior quality and lasting field service you can depend on. 40-round capacity. Made in USA.